"If you think that people won’t share your secrets with others, you are probably mistaken.

I can feel you instantly balking at this statement. The mere thought that your friends or family could betray your trust is confronting. This is a reasonable enough response, the idea that those closest could be talking about you disparagingly, can create an extreme level of cognitive dissonance. It is far easier to assume that if you tell someone something in confidence, it will stay that way..."